Fix mono delay (#843)

* rtic-time: Compenstate for timer uncertainty

* Update changelog and incorrect cargo.lock in an example

* Fix Monotonic impls

* Fix tests

* Fix other monotonics, again

* Update changelog

* Fix example

* Fix DelayUs and DelayMs impls

* Minor coding style fix in u64 conversions

* Fix all changelogs

* Fix changelog

* Fix blocking DelayUs

* Minor monotonic rework

* Add delay precision test

* Add more tests

* Add rust-version tags to Cargo.toml

* Fix imxrt, rp2040 and systick timer

* Fix more monotonics

* Fix systick monotonic

* Some reverts

* Fix imxrt

* Fix nrf

* Fix rp2040

* Fix stm32

* Fix systick

* Fix rtic-time tests

* Bump to e-h.rc2

* Apply e-h.rc2 fixes to rtic-time

* Apply fixes from arbiter

* Fix clippy warning

* Minor beautification

* Revert previous changes

* Fix variable name

* Add blocking tests, but disable them by default

2 files changed, 171 insertions, 4 deletions

diff --git a/rtic-time/src/lib.rs b/rtic-time/src/lib.rs
index 0c3e3495..4c89d52c 100644
--- a/rtic-time/src/lib.rs
+++ b/rtic-time/src/lib.rs
@@ -181,22 +181,36 @@ impl<Mono: Monotonic> TimerQueue<Mono> {
         }
     }
 
-    /// Timeout after a specific duration.
+    /// Timeout after at least a specific duration.
     #[inline]
     pub async fn timeout_after<F: Future>(
         &self,
         duration: Mono::Duration,
         future: F,
     ) -> Result<F::Output, TimeoutError> {
-        self.timeout_at(Mono::now() + duration, future).await
+        let now = Mono::now();
+        let mut timeout = now + duration;
+        if now != timeout {
+            timeout = timeout + Mono::TICK_PERIOD;
+        }
+
+        // Wait for one period longer, because by definition timers have an uncertainty
+        // of one period, so waiting for 'at least' needs to compensate for that.
+        self.timeout_at(timeout, future).await
     }
 
-    /// Delay for some duration of time.
+    /// Delay for at least some duration of time.
     #[inline]
     pub async fn delay(&self, duration: Mono::Duration) {
         let now = Mono::now();
+        let mut timeout = now + duration;
+        if now != timeout {
+            timeout = timeout + Mono::TICK_PERIOD;
+        }
 
-        self.delay_until(now + duration).await;
+        // Wait for one period longer, because by definition timers have an uncertainty
+        // of one period, so waiting for 'at least' needs to compensate for that.
+        self.delay_until(timeout).await;
     }
 
     /// Delay to some specific time instant.
diff --git a/rtic-time/src/monotonic.rs b/rtic-time/src/monotonic.rs
index ad79bf20..0c0d6f35 100644
--- a/rtic-time/src/monotonic.rs
+++ b/rtic-time/src/monotonic.rs
@@ -10,6 +10,9 @@ pub trait Monotonic {
     /// The time at time zero.
     const ZERO: Self::Instant;
 
+    /// The duration between two timer ticks.
+    const TICK_PERIOD: Self::Duration;
+
     /// The type for instant, defining an instant in time.
     ///
     /// **Note:** In all APIs in RTIC that use instants from this monotonic, this type will be used.
@@ -65,3 +68,153 @@ pub trait Monotonic {
     /// NOTE: This may be called more than once.
     fn disable_timer() {}
 }
+
+/// Creates impl blocks for `embedded_hal::delay::DelayUs`,
+/// based on `fugit::ExtU64Ceil`.
+#[macro_export]
+macro_rules! embedded_hal_delay_impl_fugit64 {
+    ($t:ty) => {
+        impl ::embedded_hal::delay::DelayNs for $t {
+            fn delay_ns(&mut self, ns: u32) {
+                use ::fugit::ExtU64Ceil;
+
+                let now = Self::now();
+                let mut done = now + u64::from(ns).nanos_at_least();
+                if now != done {
+                    // Compensate for sub-tick uncertainty
+                    done += Self::TICK_PERIOD;
+                }
+
+                while Self::now() < done {}
+            }
+
+            fn delay_us(&mut self, us: u32) {
+                use ::fugit::ExtU64Ceil;
+
+                let now = Self::now();
+                let mut done = now + u64::from(us).micros_at_least();
+                if now != done {
+                    // Compensate for sub-tick uncertainty
+                    done += Self::TICK_PERIOD;
+                }
+
+                while Self::now() < done {}
+            }
+
+            fn delay_ms(&mut self, ms: u32) {
+                use ::fugit::ExtU64Ceil;
+
+                let now = Self::now();
+                let mut done = now + u64::from(ms).millis_at_least();
+                if now != done {
+                    // Compensate for sub-tick uncertainty
+                    done += Self::TICK_PERIOD;
+                }
+
+                while Self::now() < done {}
+            }
+        }
+    };
+}
+
+/// Creates impl blocks for `embedded_hal_async::delay::DelayUs`,
+/// based on `fugit::ExtU64Ceil`.
+#[macro_export]
+macro_rules! embedded_hal_async_delay_impl_fugit64 {
+    ($t:ty) => {
+        impl ::embedded_hal_async::delay::DelayNs for $t {
+            #[inline]
+            async fn delay_ns(&mut self, ns: u32) {
+                use ::fugit::ExtU64Ceil;
+                Self::delay(u64::from(ns).nanos_at_least()).await;
+            }
+
+            #[inline]
+            async fn delay_us(&mut self, us: u32) {
+                use ::fugit::ExtU64Ceil;
+                Self::delay(u64::from(us).micros_at_least()).await;
+            }
+
+            #[inline]
+            async fn delay_ms(&mut self, ms: u32) {
+                use ::fugit::ExtU64Ceil;
+                Self::delay(u64::from(ms).millis_at_least()).await;
+            }
+        }
+    };
+}
+
+/// Creates impl blocks for `embedded_hal::delay::DelayUs`,
+/// based on `fugit::ExtU32Ceil`.
+#[macro_export]
+macro_rules! embedded_hal_delay_impl_fugit32 {
+    ($t:ty) => {
+        impl ::embedded_hal::delay::DelayNs for $t {
+            fn delay_ns(&mut self, ns: u32) {
+                use ::fugit::ExtU32Ceil;
+
+                let now = Self::now();
+                let mut done = now + ns.nanos_at_least();
+                if now != done {
+                    // Compensate for sub-tick uncertainty
+                    done += Self::TICK_PERIOD;
+                }
+
+                while Self::now() < done {}
+            }
+
+            fn delay_us(&mut self, us: u32) {
+                use ::fugit::ExtU32Ceil;
+
+                let now = Self::now();
+                let mut done = now + us.micros_at_least();
+                if now != done {
+                    // Compensate for sub-tick uncertainty
+                    done += Self::TICK_PERIOD;
+                }
+
+                while Self::now() < done {}
+            }
+
+            fn delay_ms(&mut self, ms: u32) {
+                use ::fugit::ExtU32Ceil;
+
+                let now = Self::now();
+                let mut done = now + ms.millis_at_least();
+                if now != done {
+                    // Compensate for sub-tick uncertainty
+                    done += Self::TICK_PERIOD;
+                }
+
+                while Self::now() < done {}
+            }
+        }
+    };
+}
+
+/// Creates impl blocks for `embedded_hal_async::delay::DelayUs`,
+/// based on `fugit::ExtU32Ceil`.
+#[macro_export]
+macro_rules! embedded_hal_async_delay_impl_fugit32 {
+    ($t:ty) => {
+        impl ::embedded_hal_async::delay::DelayNs for $t {
+            #[inline]
+            async fn delay_ns(&mut self, ns: u32) {
+                use ::fugit::ExtU32Ceil;
+                Self::delay(ns.nanos_at_least()).await;
+            }
+
+            #[inline]
+            async fn delay_us(&mut self, us: u32) {
+                use ::fugit::ExtU32Ceil;
+                Self::delay(us.micros_at_least()).await;
+            }
+
+            #[inline]
+            async fn delay_ms(&mut self, ms: u32) {
+                use ::fugit::ExtU32Ceil;
+                Self::delay(ms.millis_at_least()).await;
+            }
+        }
+    };
+}